A power augmentation process for a gas turbine in which the intake air is humidified, and thus cooled, is performed to produce more power for the gas turbine. Water is added to the intake air to saturate and cool the air as it enters the gas turbine. The cooler, and thus denser, air augments the power of the gas turbine. A power augmentation system may include a controller, a fluid delivery skid, and an injection apparatus with multiple spray arrays. The controller provides commands to the fluid delivery skid, which supplies fluid to the injection apparatus.
A pump that produces high pressure fluid is often utilized as part of the fluid delivery skid to produce a spray, to be emitted from the spray arrays of the injection apparatus, with necessary small diameter droplets. The droplets are required to be of a small diameter to minimize potential damage to the gas turbine as well as to maximize the rate of evaporation inside the gas turbine intake. The high pressure from the pump limits the pump's range of operation if only one spray array is used. A single spray array typically has a water flow range of operation of 1.3 times its minimum flow. However, a water flow range of 2-3 times its minimum flow is necessary to cover the temperature and humidity conditions needed for power augmentation. To meet the water flow range of 2-3 times the spray array's minimum flow, some power augmentation systems employ multiple stages. Each stage includes one pump and is independently turned on and off to allow different flow ranges to cover the necessary flow range. Each pump is held at a constant speed and receives the unused amount of the flow at its entrance as part of a recirculation process. Such a system, however, requires multiple pumps, which increases the cost of the power augmentation system as well as adds to the size of the fluid delivery skid. For example, a system may require as many as six or more pumps. Moreover, the multiple pumps create difficulty in adding redundancy. The recirculation process, which is necessary to make use of the unused flow, requires recirculation valves that may typically erode and prove to be unreliable. Thus, a system is needed to more efficiently and effectively provide high pressure fluid for power augmentation of a gas turbine.